1. Field of the Invention
The present invention relates to a method for planarizing a circuit board, and a method for manufacturing a semiconductor device.
2. Description of the Related Art
Semiconductor devices contribute to the reduction in size of information communication equipment, official electronic equipment, household electronic equipment, industrial electronic equipment such as measuring apparatuses and assembling robots, medical electronic equipment, and electronic toys, and facilitates the miniaturization thereof.
The manufacturing of semiconductor devices requires semiconductor elements and wiring boards for mounting them thereon. As technology for mounting a semiconductor element on a wiring board, a wire bonding method has been the mainstream conventionally. However, a flip-chip method capable of reducing the mounting area of semiconductor elements has become the mainstream in recent years. In a wiring board on which a semiconductor element is to be mounted, in mounting a semiconductor element by a wire bonding method, the electrodes on the semiconductor element are bonded outward to the electrodes of the wiring board placed outside the semiconductor element by wire, respectively, and hence the electrodes on the wiring board may be placed with a larger pitch than the pitch of electrodes of the semiconductor element. Contrarily, in mounting a semiconductor element with a flip-chip method, the electrodes of the semiconductor element must be located corresponding to the electrodes of the wiring board in a one-to-one relationship. Therefore, as wiring board for mounting a semiconductor element thereon with a flip-chip method, a high-density board, i.e., a board on which a fine line is to be formed is desirable. Further, a reduction in size of a semiconductor device requires a board to which a wiring layer is connected through an inner via.
It is a ceramic multi-layer printed circuit board to satisfy the foregoing demands. However, a ceramic plate board generally has a limitation on its cost reduction as compared with resin boards such as glass epoxy boards, which actually restricts the introduction into consumer-electronics products.
A resin plate board has a higher possibility that a larger cost reduction can be achieved due to its manufacturing method than in the case of a ceramic plate board. However, the resin board has a lower rigidity than that of a ceramic plate board, and hence there occur nonuniform wiring density, and deformation when the board decreases in thickness, resulting in a difficulty in flip-chip mounting of a semiconductor element.
In view of the foregoing, it is therefore an object of the present invention to provide a method for manufacturing a semiconductor device with stability.
A method for planarizing a circuit board according to the present invention, comprises: a step of fixing a circuit board having wiring layers on both sides to a board having a flat surface through an adhesive layer, wherein the circuit board is pressed from above by a flat member on fixing thereof.
A method for manufacturing a semiconductor device according to the present invention, comprises: a step of fixing a circuit board having wiring layers on both sides to a board having a flat surface through an adhesive layer; a step of mounting a semiconductor element so that a plurality of electrodes on the semiconductor element are face-down bonded to the exposed wiring of the fixed circuit board in a one-to-one relationship; a step of filling the clearance between the circuit board and the semiconductor element with an insulating resin paste; a step of curing the insulating resin paste; and a step of peeling off the circuit board on which the semiconductor element is mounted from the interface with the adhesive layer on the board having a flat surface, wherein the circuit board is pressed from above by a flat member on fixing the circuit board.
A method for manufacturing a semiconductor device according to the present invention, comprises: a step of fixing a circuit board having wiring layers on both sides to a motherboard having a flat surface through an adhesive layer; a step of mounting a semiconductor element so that a plurality of electrodes on the semiconductor element are face-down bonded to the exposed wiring of the fixed circuit board in a one-to-one relationship; a step of filling the clearance between the circuit board and the semiconductor device with an insulating resin paste; and a step of curing the insulating resin paste, wherein the circuit board is pressed from above by a flat member on fixing the circuit board.